Hospital beds comprise complex mechanical and electronic components for movement, functionality and convenience.
Foot brakes of prior art hospital beds are typically located on the side under the bed. There are certain disadvantages associated with such foot brakes. For example, during activation, a user such as a nurse has to hold on to the bed, balance on one foot and stretch the other foot under the bed to engage or disengage the brake. As such, if the side rail is in the lower position, visibility may be reduced. In addition, if the patient is exiting the bed, the bed may move, which may be unsafe. Furthermore, the weights of present day beds and patients are relatively large, requiring sufficient braking force to hold a bed in a desired location in a hospital.
There is a need for a braking system which is convenient and safe to use. Such a system can be powered in any manner. There is a further need for a braking mechanism that can be manually overridden such as if there is a power failure.
Generally, a bed is moved by a series of internal motors and controlled by means of an interface that can be used by users such as hospital personnel or the patient to adjust the bed to suit the comfort and needs of the patient. For safety reasons, the movement of the bed is quite slow and there is a need for an override control, to quickly and efficiently bring the bed into a relatively flat position in case of emergency or for routine tasks such as cleaning, patient transfer or surgery. In past designs, this override function has been initiated through hand controls, foot controls, or a combination of hand and foot controls. In an emergency situation, it is desirable to reposition a bed quickly and easily into a CPR or Trendelenburg position, to facilitate administration of CPR or other resuscitation efforts. The manual- or motor-driven mechanism utilized to raise and lower the Fowler section typically moves too slowly to be acceptable in an emergency situation. Accordingly, emergency releases have been developed to quickly disengage the Fowler section from the drive mechanism to allow for rapid movement, however, these arrangements can be complex, bulky, expensive and difficult to engage and disengage.
Movement of the foot-end of a hospital bed to various positions that are not aligned with the remainder of the bed, such as a chair position, is difficult when it forms part of the main bed frame
For a patient support apparatus in which movement of the Fowler section is effected by a motor-driven mechanism, it would be advantageous to be able to increase the speed at which the Fowler section could be lowered for CPR and Trendelenburg, beyond that speed which is currently obtainable with the motor-driven mechanism powered by a conventional electrical power source.
Early designs of adjustable beds often employed the concept of a hand crank and gearing to adjust the height of a bed. Such manual systems suffer from the need for considerable physical effort to adjust the bed height. Other designs include elevation systems incorporating mechanical jacks using hydraulic piston cylinders or screw drives to adjust the height of the hospital bed. Such hydraulic systems are known to be relatively expensive and prone to leakage. Additionally, prior mechanical systems suffer from excessive complexity, excessive size, a lack of load capacity, and manufacturing difficulties.
Hospital bed side rails of the prior art comprise support arms which form undesirable pinch points for users. The movement of such side rails from the deployed to the stowed positions is often hampered by side rail oscillations. The side rail falls due to gravity and the movement can jar the bed and disturb patients.
In addition, the patient support apparatus of the prior art relies on batteries to provide all power to the bed's electronic systems. When the battery power runs out, the battery itself must be recharged before power can be supplied to the electronics. This is problematic in circumstances where the life of the battery itself has run out or in settings where a suitable power supply to recharge the battery is not available.
In existing apparatuses, the control interface is located on the side or foot-end of a bed. Often, the operator directs movement of the bed from the head-end by pushing on the head-end or push handles located at the head-end. In the event the position of the patient needs to be adjusted while a prior art hospital bed is in motion, the operator has to stop the bed and move around the bed in order to access the bed control interface. If the bed is in a confined space, such as a narrow corridor or elevator, this action may be difficult to execute and result in an undesirable delay in effecting the change in position of the patient.
Currently, the angular position of the patient can be determined by measuring the patient's current position with respect to a plane of reference (e.g., the floor or the bed frame). This technique, however, suffers from the drawback that any misalignment in the frame of reference severely affects the integrity of the sensed angular position. Another method for inclinometry is by way of gravitational accelerometers. When the accelerometer is in a stationary position, the only force acting on it is the vertical gravitational force having a constant acceleration. Accordingly, the angular position of the patient can be calculated by measuring the deviation in the inclination angle between the inclination axis and the vertical gravitational force. Although the accelerometers can provide an effective way to measure the inclination in the patient's position, the resolution of the gravitational accelerometers is restricted to a limited range of inclination angles.
Currently, nurses and other hospital staff hang pumps (or other hospital equipment) on the top edge of the footboards of hospital beds. Since footboards were not designed to support the hanging of pumps (or other hospital equipment), this current practice reduces access to the controls on footboards, damages foot controls and footboards, generates bed motions and causes damage to pumps (and other equipment) that fall from their hangers.
Ordinarily, there is a tendency for detached headboards or footboards placed in an upright position against an object or structure to slip, thereby causing the headboard or footboard to fall and potentially suffer damage. This is a particularly acute concern in the situation of a medical emergency during which headboards and footboards may need to be removed and set aside in haste. In a busy hospital, a discarded headboard or footboard that has fallen to the floor creates a tripping hazard to both staff, who may be carrying equipment or medication and thus have an obstructed view of the floor, and patients, who may have compromised mobility owing to illness. Preventing slippage, therefore, reduces the likelihood of personal injury stemming from hastily removed headboards and footboards.
Existing motorized hospital beds utilize a single speed or multiple defined and preprogrammed speeds for bed movement resulting in the user having to manually switch speeds. Variable speeds in these beds are not automatic.
Therefore, there is a need to provide a patient support apparatus such as a hospital bed which overcomes the problems of the prior art.